Detection of viral DNA to evaluate outcome of antiviral treatment of patients with recurrent genital herpes

Once daily valacyclovir for reducing viral shedding in subjects newly diagnosed with genital herpes

OBJECTIVE

Genital herpes (GH) recurrences and viral shedding are more frequent in the first year after initial HSV-2 infection. The objective of this study was to provide the first evaluation of valacyclovir 1 g once daily compared to placebo in reducing viral shedding in subjects newly diagnosed with GH.

METHODS

70 subjects were randomized to receive valacyclovir 1 g daily or placebo in a crossover design for 60 days with a 7-day washout period. A daily swab of the genital/anal-rectal area was self-collected for HSV-2 detection by PCR. Subjects attended the clinic for routine study visits and GH recurrence visits. Treatment differences were assessed using a nonparametric crossover analysis.

RESULTS

52 subjects had at least one PCR measurement in both treatment periods and comprised the primary efficacy population. Valacyclovir significantly reduced HSV-2 shedding during all days compared to placebo (mean 2.9% versus 13.5% of all days (P < .01), a 78% reduction). Valacyclovir significantly reduced subclinical HSV-2 shedding during all days compared to placebo (mean 2.4% versus 11.0% of all days (P < .01), a 78% reduction). However, 79% of subjects had no GH recurrences while receiving valacyclovir compared to 52% of subjects receiving placebo (P < .01).

CONCLUSION

In this study, the frequency of total and subclinical HSV-2 shedding was greater than reported in earlier studies involving subjects with a history of symptomatic genital recurrences. Our study is the first to demonstrate a significant reduction in viral shedding with valacyclovir 1 g daily compared to placebo in a population of subjects newly diagnosed with HSV-2 infection.

The effect of daily valacyclovir suppression on herpes simplex virus type 2 viral shedding in HSV-2 seropositive subjects without a history of genital herpes

BACKGROUND

A substantial number of HSV-2 seropositive individuals lack a history of clinically recognized genital herpes. These individuals can transmit disease during periods of asymptomatic viral shedding. The frequency of asymptomatic shedding and the efficacy of antiviral therapy in reducing shedding has not been assessed in this population.

OBJECTIVE

To compare the effect of valacyclovir 1 g once daily for 60 days versus placebo on asymptomatic viral shedding in immunocompetent, HSV-2 seropositive subjects without a history of symptomatic genital herpes infection.

STUDY DESIGN

Seventy-three subjects were randomized to receive valacyclovir 1 g daily or placebo for 60 days each in a 2-way crossover design. A daily swab of the genital area was self-collected for HSV-2 detection by polymerase chain reaction.

RESULTS

Fifty-six subjects with at least 1 polymerase chain reaction measurement in both treatment periods comprised the primary efficacy population. Valacyclovir significantly reduced shedding during subclinical days compared to placebo [mean, 1.5% vs. 5.1% of subclinical days (P <0.001), a 71% reduction]. Eighty-four percent of subjects had no shedding while receiving valacyclovir versus 54% of subjects on placebo (P <0.001). Eighty-eight percent of patients receiving valacyclovir had no recognized signs or symptoms versus 77% for placebo (P = 0.033). Valacyclovir was not associated with any safety risk compared with placebo.

CONCLUSIONS

In this study, asymptomatic viral shedding occurred in a substantial number of HSV-2 seropositive subjects without a history of genital herpes. Valacyclovir 1 g daily significantly reduced asymptomatic shedding compared with placebo in this population.

From the NIH: proceedings of a workshop on the importance of self-obtained vaginal specimens for detection of sexually transmitted infections

On June 27, 2006, the NIH conducted a workshop to review published data and current field practices supporting the use of self-obtained vaginal swabs (SOVs) as specimens for diagnosis of sexually transmitted infections (STIs). The workshop also explored the design of studies that could support FDA clearance of SOVs for STI testing, particularly for specimens collected in nonclinical settings including patients' homes. This report summarizes the workshop findings and recommendations. Participants concluded that self-obtained vaginal swabs are well accepted by women of all ages and that SOVs perform as well as or better than other specimen types for Chlamydia trachomatis and Neisseria gonorrhoeae detection using transcription-mediated amplification. In addition, workshop participants recommended the validation of SOV testing by public health practitioners and manufacturers of STI diagnostic tests to expedite incorporation of SOVs as a diagnostic option in clinical and nonclinical settings for Chlamydia trachomatis and Neisseria gonorrhoeae testing. Similarly, SOVs should be explored for use in the diagnosis of other sexually transmitted pathogens.

Effect of valacyclovir on viral shedding in immunocompetent patients with recurrent herpes simplex virus 2 genital herpes: a US-based randomized, double-blind, placebo-controlled clinical trial

OBJECTIVE

To determine the efficacy of daily suppressive therapy with a 1-g dose of valacyclovir in reducing total (clinical and subclinical) herpes simplex virus 2 (HSV-2) shedding compared with placebo in Immunocompetent patients diagnosed as having recurrent HSV-2 genital herpes.

PATIENTS AND METHODS

From June 18, 2004, to December 17, 2004, patients from 27 US sites with a history of 6 or more genital herpes recurrences per year were randomized in a 3:1 ratio to receive 1 g/d of valacyclovir or placebo. During the double-blind suppressive therapy, patients were provided with the study drug (500-mg valacyclovir caplets or matching placebo) and Instructed to take 2 caplets once daily without regard to meals for 60 days. Daily genital and anal or rectal swabs were self-collected during the 60-day study period for evaluation of HSV-2 viral shedding as determined by quantitative type-specific polymerase chain reaction assay.

RESULTS

One hundred fifty-two patients were randomized into this study, 43 to placebo and 109 to 1 g/d of valacyclovir. A total of 134 completed the study (40 placebo [93%], 94 valacyclovir [86%]), and 18 prematurely withdrew (3 placebo [7%], 15 valacyclovir [14%]). Valacyclovir significantly reduced the percentage of days with total (clinical and subclinical) HSV-2 shedding throughout 60 days compared with placebo. In the intent-to-treat population, a 71% reduction in total shedding (P < .001), a 58% reduction in subclinical shedding (P < .001), and a 64% reduction in clinical shedding (P = .01) were observed. Valacyclovir was not associated with any significant toxic effects compared with placebo.

CONCLUSION

This study demonstrated that 1 g/d of valacyclovir administered for 60 days was generally well tolerated and was an effective suppressive therapy that significantly reduced total (clinical and subclinical) HSV-2 shedding compared with placebo in immunocompetent patients diagnosed as having recurrent HSV-2 genital herpes.

[Up to date in sexually transmitted infections: epidemiology, diagnostic approaches and treatments]

In the last years, there have been important advances in sexually transmitted infections such as genome sequencing of Treponema pallidum, Chlamydia trachomatis or Mycoplasma genitalium; the new taxonomic position of Calymmatobacterium granulomatis; commercial diagnostic systems based on nucleic acid amplification; the emergence of quinolone resistance in Neisseria gonorrhoeae; new therapeutic approaches in vulvovaginal candidiasis that include boric acid; the demonstration that valacyclovir reduces the risk of transmission of genital herpes or the availability of immune-response modifier in the treatment of genital warts, and that are questions in the goal of this review. Viral hepatitis and HIV were no reviewed by space reasons.

Augmentation of B7 expression by herpes simplex virus antigen

B7 costimulation plays a major role in herpes simplex virus (HSV) immunity. Effects of immunoregulatory cytokines (interferon-gamma [IFN-gamma] and interleukin-10 [IL-10]) and HSV antigens on B7-1 (CD80) and B7-2 (CD86) expression on monocytes during HSV-2 infection were investigated using flow cytometry. Our results demonstrate that HSV-2 infection effects the expression of B7 isoforms (B7-1 and B7-2) on monocytes in two ways, with opposing outcomes. It abrogates the IFN-gamma upregulation of B7-1 and B7-2 and also augments expression of B7-1 and B7-2 on monocytes through an IFN-gamma independent mechanism. The clinical significance of these opposing effects may be related to the pathogenesis of recurrent HSV disease in immunocompetent hosts.

Dysregulated expression of IFN-gamma and IL-10 and impaired IFN-gamma-mediated responses at different disease stages in patients with genital herpes simplex virus-2 infection

Cell-mediated T-helper type-1 (Th1) responses play a vital role in the immunopathogenesis of genital infections caused by herpes simplex virus 2 (HSV-2). We investigated the role of Th responses in HSV-2 infection at different disease stages by analysing the production of Th cytokines in HSV-stimulated peripheral blood mononuclear cells (PBMCs). IFN-gamma production decreased over time following a recurrence, whereas levels of IL-10, and to a lesser extent IL-2, remained elevated during this period. In addition, PBMCs from asymptomatic seropositive individuals produced high levels of IFN-gamma and low levels of IL-10, in contrast to individuals with a history of genital ulcers. Following a recurrence, virus copy number in the genital lesions decreased progressively over time, in a manner similar to IFN-gamma production by HSV-2-stimulated PBMCs. Enhanced production of IFN-gamma may modulate HSV replication and B7 expression on monocytic cells of HSV-infected individuals. In contrast to seronegative controls, IFN-gamma failed to enhance B7 expression on monocytic cells of HSV-infected individuals. In addition, monocytic cells from HSV-2-infected individuals with recurrent disease supported greater HSV replication than did those of HSV-infected asymptomatic individuals or seronegative controls. Furthermore, addition of IFN-gamma resulted in enhanced HSV replication in monocytic cells of HSV-infected individuals with recurrent disease, in contrast to the inhibition observed in HSV-seropositive asymptomatic individuals and seronegative controls. Taken together, our results suggest that dysregulated production of IFN-gamma at different disease stages and the impaired ability of monocytic cells to respond to IFN-gamma may play a role in the pathogenesis of recurrent genital herpes disease.

Identification of herpes simplex virus genital infection: comparison of a multiplex PCR assay and traditional viral isolation techniques

Genital herpes simplex virus (HSV) is of major public health importance, as indicated by the marked increase in the prevalence of genital herpes over the past two decades. Viral culture has traditionally been regarded as the gold standard for diagnosis. In this study, we compared viral culture and the amplification of HSV DNA by the polymerase chain reaction (PCR) with respect to sensitivity, cost, clinical utility, and turnaround time. Patient sample swabs from 100 individuals were inoculated onto MRC-5 cells for isolation. Positive results were confirmed via a direct fluorescent antibody technique, and serotyping, when requested, was performed using HSV-1 and -2-type-specific sera. PCR techniques employed an extraction step of the same initial swab specimen, followed by PCR amplification, using a multiplex assay for HSV-1, 2 DNA. HSV-positive results were found in 32/100 samples via culture and in 36/100 samples via PCR. PCR-positive results yielded 16 (44%) patients infected with HSV-1 and 20 (56%) patients infected with HSV-2. Turnaround time for viral culture averaged 108 hours for positive results and 154 hours for negative results; PCR turnaround time averaged 24--48 hours. Laboratory cost using viral culture was $3.22 for a negative result and $6.49 for a positive result (including direct fluorescent antibody). Serotyping added $10.88 to each culture-positive test. Although laboratory costs for PCR were higher at $8.20/sample, reimbursement levels were also higher. We propose a multiplex PCR assay for diagnosis of HSV-1 and HSV-2 from patient swabs for use in a routine clinical laboratory setting. This assay offers increased sensitivity, typing, and improved turnaround time when compared with traditional viral culture techniques. Although it appears that PCR testing in a routine clinical laboratory setting is cost prohibitive compared with the case of nonserotyped viral culture, it may be very useful when clinical utility warrants distinguishing between HSV 1 and 2 and may be cost effective when reimbursement issues are examined.

Current recommendations for the treatment of genital herpes

The incidence of genital herpes continues to increase in epidemic-like fashion. Aciclovir (acyclovir) has been the original gold standard of therapy. The recent addition of famciclovir and valaciclovir as antiherpes drugs has improved convenience as well as the efficacy of treatment. Although aciclovir remains a widely prescribed and reliable drug, its administration schedule falls short of the ease of usage that the newer nucleoside analogues offer, for both episodic and suppressive therapy. Suppression of symptomatic disease and asymptomatic shedding from the genitalia have both become popular approaches, if not the primary targets of antiviral therapy. Knowing that asymptomatic disease leads to most cases of transmission strongly suggests that suppression with antiviral agents could reduce transmission risk in discordant couples. Unfortunately, the role for antivirals in reducing transmission remains to be proven in clinical trials. Neonatal herpes is now successfully treated using aciclovir. Current randomised clinical trials are examining aciclovir and valaciclovir administration, as well as safety and efficacy for post-acute suppressive therapy. Prevention of recurrences in pregnancy is also a topic under investigation, with a view to reducing the medical need for Cesarean section, or alternatively (and far less likely to be accomplished) to protect the neonate. Although resistance is largely limited to the immunocompromised and a change in resistance patterns is not expected, several drugs are available for the treatment of aciclovir-resistant strains of herpes simplex. Foscarnet is the main alternative with proven efficacy in this setting. Unfortunately, administration of foscarnet requires intravenous therapy, although a single anecdote of topical foscarnet efficacy in this setting has been published. Alternatives include cidofovir gel, which is not commercially available but can be formulated locally from the intravenous preparation. Less effective alternatives include trifluridine and interferon. Future possibilities for treatment of genital herpes include a microparticle-based controlled-release formulation of aciclovir and resiquimod (VML-600; R-848). The search for an effective therapeutic vaccine for genital herpes has not been successful to date, although a live virus glycoprotein H-deficient (DISC) vaccine is currently in clinical trials. Recent data suggest that seronegative women are protected (albeit, not fully) by a glycoprotein D recombinant vaccine with adjuvant. Despite the established safety and convenience of current treatment options, better suppressive options and topical treatment options are much needed. Studies using existing agents as potential tools to avoid Cesarean section, or transmission to neonate or partner are ongoing. Both vaccines and antivirals may eventually play a role in prevention of infection.

The Use of Molecular Techniques for the Diagnosis and Epidemiologic Study of Sexually Transmitted Infections

Molecular diagnostic tests are more sensitive and, in many cases, more specific than conventional laboratory methods for the detection of sexually transmitted infections. Here, we review recently developed molecular methods for the diagnosis and subtyping of the most common sexually transmitted infections: infections caused by Chlamydia trachomatis, Neisseria gonorrhoeae, human papillomavirus, Trichomonas vaginalis, and the agents of genital ulcer disease (Haemophilus ducreyi, herpes simplex virus, Treponema pallidum, and Calymmatobacterium granulomatis). We also provide an overview of the laboratory diagnostic tests and clinical specimens to use when infection with these agents is suspected.

The clinical utility of viral quantitation using molecular methods

BACKGROUND

The quantitation of viral nucleic acids in biological fluids has become increasingly desirable over the past several years. To this end, a number of quantitative molecular procedures have been developed.

OBJECTIVES

The objective was to review the current literature on the molecular techniques used in the quantitation of viral nucleic acids and to assess the appropriateness of these methods for clinical use.

RESULTS

Assays involving both target and signal amplification are now available for the accurate and precise quantitation of viral burden in infected patients. These methods include quantitative polymerase chain reaction (PCR), branched chain signal amplification (bDNA), nucleic acid sequence-based amplification (NASBA) and the SHARP signal and hybrid capture systems. Our understanding of the natural history and pathogenesis of viruses such as the human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) may be greatly facilitated by accurate determinations of viral and infected cell burden. Quantitation of viral load in infected individuals may also be useful to assess disease progression, monitor the efficacy of therapy and to predict treatment failure and the emergence of drug-resistant viruses.

CONCLUSION

Precise, accurate and reproducible quantitation of viral load is now feasible. Molecular assays for viral quantitation should have a considerable impact on medical research and clinical care.

Detection and direct typing of herpes simplex virus in perianal ulcers of patients with AIDS by PCR

The presence of herpes simplex virus type 1 (HSV-1) and HSV-2 in perianal ulcerations of 41 AIDS patients was assessed by virus culture and a type-specific PCR-based assay. HSV was isolated from the lesion site in 24 of 41 (58.5%) patients, and HSV DNA was detected by PCR in all 24 (100%) of these specimens. Additionally, PCR was used to detect HSV DNA in 12 of 17 (70.5%) HSV culture-negative samples. Thus, HSV genomic sequences could be demonstrated in 36 of 41 (87.8%) perianal ulcers in this series. Full agreement in HSV typing by either immunodot assay or PCR was seen in 24 samples that were positive by both virus culture and PCR. HSV-2 was demonstrated in 35 of 36 (97.2%) HSV-positive samples.

Rapid detection and typing of herpes simplex virus DNA in clinical specimens by the hybrid capture II signal amplification probe test

A second-generation signal amplification, nucleic acid-based test for the rapid detection and typing of herpes simplex virus (HSV) DNA was developed and evaluated with artificial and clinical specimens. The analytical sensitivity of the Hybrid Capture II (HC II) HSV DNA assay was determined by testing either cloned HSV DNA or total genomic HSV DNA titrations and resulted in detection thresholds of between 5 x 10(3) and 1 x 10(4) copies per assay. Specificity was assessed by testing a panel of bacteria and viruses commonly found in the female genital tract. Sensitivity was assessed by testing 112 ulcerative genital lesions by the HC II assay and comparing the results to those obtained by routine cell culture. Discrepant results were resolved by PCR testing. After resolution of the discrepant results, the sensitivity of the HC II assay compared to the consensus result (the results of two of three tests, the HC II assay, culture, and PCR, were in agreement) was 93.2% (41 of 44 specimens), and the specificity was 100% (60 of 60 specimens). Culture gave a sensitivity of 84.1% (37 of 44 specimens) and a specificity of 100% (60 of 60 specimens) compared to the consensus result. The results of HSV typing by the HC II assay and culture agreed in all cases. The HC II assay is a rapid and accurate assay for detecting and typing HSV types 1 and 2, with a sensitivity comparable to that of culture and greater ease of use than culture.

Evaluation of a non-isotopic polymerase chain reaction assay for detection in clinical specimens of herpes simplex virus type 2 DNA. Canadian Women's HIV Study Group

BACKGROUND

PCR assays for detection of herpes simplex virus DNA sequences in clinical specimens are more sensitive than cell culture.

OBJECTIVE

A non-isotopic PCR assay (glycoprotein B HSV-2 assay, Roche Molecular Systems) for detection of HSV-2 DNA sequences was evaluated on 234 clinical specimens.

STUDY DESIGN

A total of 125 patients (73 women, 40 men, 12 unknown) provided 162 samples contained in viral transport medium. Samples were first inoculated in cell culture, centrifuged at 12,000 x g, lyzed and kept frozen. A total of 77 women provided 42 cervicovaginal lavages and 30 vaginal tampons that were lyzed, tested with two isotopic HSV-2 PCR assays and kept frozen. All these samples were subsequently thawed and amplified with the glycoprotein B HSV-2 assay using generic primers for HSV glycoprotein B gene. Amplicons were captured on microplates with a HSV-2-specific probe and were detected with avidin-peroxidase and substrate.

RESULTS

Of the 162 samples submitted to viral culture, HSV-2 was isolated from 73 while 89 did not contain HSV-2. All the 73 specimens with culture-proven HSV-2 infections tested positive with glycoprotein B HSV-2 assay (sensitivity of 100%). Herpesviruses other than HSV-2 were isolated from 34 samples that were negative with glycoprotein B HSV-2 assay. Two culture-negative samples tested positive in the glycoprotein B HSV-2 assay (specificity of 98.7%). The latter samples could not be retested in confirmatory isotopic HSV-2 PCR tests. HSV-2 DNA sequences could also be detected directly in cervical lavages or vaginal tampons from 13 women with the glycoprotein B HSV-2 assay.

CONCLUSION

Detection and typing of HSV-2 in clinical samples, including those collected in viral transport medium, can be accomplished with PCR assays using the AMPLICOR format.

Evaluation of a quantitative competitive PCR assay for measuring herpes simplex virus DNA content in genital tract secretions

Previous studies have shown an association between the approximate titer of herpes simplex virus (HSV) DNA in clinical specimens and the ability to isolate HSV from genital secretions. To control for variance in amplification conditions, we developed a competitive quantitative PCR (QC PCR) for the detection of HSV DNA. The assay accurately measured from 10 to 10(6) copies of HSV DNA. We compared the QC PCR with our previous semiquantitative detection method and found concordance for 61 of 63 positive specimens. We also evaluated the HSV DNA content from individual swabs of genital secretions obtained from individual sites of the genital tract (cervix, vulva, and rectum) with that from one swab with secretions from all three sites. The concordance for detecting HSV DNA was 91%; for only 4 of 143 collection days was there a > 1 log difference between the two collection methods. A single swab with secretions from all three genital sites and evaluated in a QC PCR format can accurately measure the frequency of subclinical and clinical shedding of HSV and the titer of HSV shed from the genital region. Such an approach should be very useful in the evaluation of antiviral chemotherapy for HSV.